[FIX] website_sale: "From website" filter

This filter must be added in the regular searchview,
and not have his own search view.

Without this:
 - view_sales_order_filter_ecommerce is a not search view
 for the sale orders, having the same priority than the regular one,
 and therefore this view can be loaded by default for other menus
 (In this case, this was for the menu Website Admin > Orders).
 e.g. Clicking on the `Sales` stat button on a contact no longer
 filtered the orders of this contact, but displayed all the orders,
 because it was this view which was loaded instead of the regular one.
 - In Website Admin > Orders, it was simply not possible to type a string
   and search for it in the search bar.

addons/website_sale/views/backend.xml

@@ -24,8 +24,9 @@
     <record id="view_sales_order_filter_ecommerce" model="ir.ui.view">
         <field name="name">sale.order.ecommerce.search.view</field>
         <field name="model">sale.order</field>
+        <field name="inherit_id" ref="sale.view_sales_order_filter"/>
         <field name="arch" type="xml">
-            <search string="eCommerce">
+            <search>
                 <filter string="From Website" name="from_website" domain="[('team_id.website_ids', '!=', False)]"/>
             </search>
         </field>